<template>
  <div class="spec-preview">
    <img :src="skuImageList[defaultIndex]?.imgUrl" />
    <div class="event" @mousemove="move"></div>
    <div class="big">
      <img :src="skuImageList[defaultIndex]?.imgUrl"  ref="bigImg"/>
    </div>
    <div class="mask" ref="mask"></div>
  </div>
</template>

<script>
  export default {
    name: "Zoom",
    props:["skuImageList"],
    data(){
      return{
        defaultIndex:0
      }
    },
    mounted() {
      this.$bus.$on("defaultImg",(index)=>{
        this.defaultIndex = index
      })
    },
    methods:{
        move(e){
            let mouseX = e.offsetX
            let mouseY= e.offsetY
            let oMask = this.$refs.mask
            let oBigImg = this.$refs.bigImg
            let MaskX = mouseX - oMask.offsetWidth /2
            let MaskY = mouseY - oMask.offsetHeight /2

            if(MaskX < 0){
                MaskX = 0
            }else if(MaskX >= oMask.offsetWidth ){
                MaskX = oMask.offsetWidth
            }

            if(MaskY < 0){
                MaskY = 0
            }else if(MaskY >= oMask.offsetHeight ){
                MaskY = oMask.offsetHeight
            }

            oMask.style.left = MaskX + "px"
            oMask.style.top = MaskY + "px"

            oBigImg.style.left = -2 * MaskX + "px"
            oBigImg.style.top = -2 * MaskY + "px"

        }
    }
  }
</script>

<style lang="less">
  .spec-preview {
    position: relative;
    width: 400px;
    height: 400px;
    border: 1px solid #ccc;

    img {
      width: 100%;
      height: 100%;
    }

    .event {
      width: 100%;
      height: 100%;
      position: absolute;
      top: 0;
      left: 0;
      z-index: 998;
    }

    .mask {
      width: 50%;
      height: 50%;
      background-color: rgba(0, 255, 0, 0.3);
      position: absolute;
      left: 0;
      top: 0;
      display: none;
    }

    .big {
      width: 100%;
      height: 100%;
      position: absolute;
      top: -1px;
      left: 100%;
      border: 1px solid #aaa;
      overflow: hidden;
      z-index: 998;
      display: none;
      background: white;

      img {
        width: 200%;
        max-width: 200%;
        height: 200%;
        position: absolute;
        left: 0;
        top: 0;
      }
    }

    .event:hover~.mask,
    .event:hover~.big {
      display: block;
    }
  }
</style>